Pump control system



Filed June 18, 1946 Patented Feb. 24, 1948 UNITED STATES PATENT OFFICEPUMP CONTROL SYSTEM Application June 18, 1946, Serial No. 677,607

8 Claims.

This invention relates to new and useful improvements in controlmechanisms for turbine driven machines, and more particularly to mechanisms for controlling operation of check valves in the discharge linesof turbine driven centrifugal pumps.

Valves of this type generally are employed in centrifugal pumpinstallations where it is necessary to check reverse flow through thepump, for example, where centrifugal pumps are used to deliver wateragainst pressure to a main or to a storage reservoir. Such centrifugalpump installations quite often are driven by means of steam turbines andif for any reason the steam pressure supply to the turbine should failor drop materially and reverse flow set in then the centrifugal pumpacts as a turbine to drive the steam turbine in the reverse directionwith probable resulting damage and injury to the turbine.

It is highly desirable therefore to prevent reverse flow through thepump by closing the check valve to prevent reverse flow, and the objectof the present invention is to provide a novel control mechanism orsystem which is operable automatically under predetermined conditions toclose the check valve in the pump discharge line before reverse flowsets in.

Another object of the invention is to provide a novel control mechanismof the stated character which is operable in response to variations inthe pressure of the steam supplied to the turbine to drive the same.

A further object of the invention is to provide a novel control havingthe features and characteristics set forth which is highly effective andfoolproof in operation and use.

These and other obiects of the invention and the various features anddetails of the construction and operation thereof are hereinafter fullvset forth and described with reference to the accompeny ng drawing inwhich the single figure is a diagrammatic showing of a steam turb ne drien centrifugal pump installation embodying a check valve controlmechanism in accordan e with the present invention.

Referring no more particularly to the drau ing, reference numeral 1designates a centrifu al pump to which ar c nnected the customary intakeand discharge lines 2 and 3 respect vel Connected in the pump dischargeline 3 adiacent the pump l is a valve 4 which is operable und r certainconditions, hereinafter more fully e plained. to close the dischargeline 3 and therehv preclude reverse flow through the pump ll Preferablythe valve 4 is of the well-known fourway hydraulic piston operated typecontrolled, in the present instance, by means of a pilot valve 5 whichis actuated by means of a solenoid device B.

In the illustrated embodiment of the invention, the construction andarrangement of the check valve 4 is such that when the solenoid i isenergized the said valve 4 is fully open to permit flow through the line8, and upon de-energization of the solenoid B said valve I is closed topreclude flow through the discharge line 3. Electrical conductors l and8 lead from suitable line conductors 9 and Ill, respectively, to thesolenoid device 6 and energization of the latter to operate pilot valve5, and thereby the check valve 4 in the pump discharge line 3, iseffected by means of a pressure operated electric switch II which isconnected in series with the said conductors l and B. In the illustratedembodiment of the present invention the contacts of the switch Hnormally are held in closed circuit relation as shown, by means of apressure responsive bellows or diaphragm device l2.

The centrifugal pump l is rotationally driven by means of a conventionaltype steam turbine l3 which is coupled to the shaft ll of said pumpthrough suitable reduction gearing. The turbine 13 in turn isrotationally driven by steam supplied to said turbine 13 at apredetermined pressure through a steam line l5 having a suitable controlvalve l6 therein. and according to the present invention the bellows ordiaphragm I2 is adapted to be operated to control the switch H inresponse to a predetermined steam pressure condition existing at anytime in the line 15 between the turbine l3 and the control valve l6therefor.

To this end, therefore, the interior of the bellows or diaphragm I2 isconnected by means of a pipe or tube l! to the interior of a chamber H3at the bottom thereof. and an intermediate portion of this pipe or tubeI1 is suitably coiled, for example, as indicated. to provide a coolingcoil or condenser l9 between the chamber l8 and the bellows or diaphragmI! of the switch II. A similar nine or tu e 20 leads from the interiorof the chamber l8 at the too thereof and has its other end connectedinto the steam line l5 between the turbine l3 and its control valve 16,while an intake pipe or tube 2|, having an inwardly opening one-waycheck valve 22 therein. leads into the chamber l8 at the top thereof andhas its other end open to the atmosphere as shown.

The bellows or diaphragm I! of the switch H thus is subjected to thepressure of the steam in the steam line I leading to the turbine I3between the latter and the control valve 16, and the bellows ofdiaphragm I2 isconstructed and calibrated to effect opening of theswitch II to break the electrical circuit to the solenoid B when thesaid steam pressure in line I5 falls below a predetermined value ashereinafter descri ed.

The cooling coil or condenser I8 provided in the pipe or tu e I'lfunctions to condense steam' flowing through the pipe or tube H from theline I5 toward the bellows or diaphragm I2 and the switch I I so thatthe steam does not reach thesee mechanisms and they are not subjected tothe high temperature of the steam and heated the'm anism or system forsteam turbine driven centrifugal pump installations which is operableautomatically under predetermined conditions to close the check valve inthe pump discharge line before reverse flow sets in. The invention alsoprovides a control mechanism of the stated character which operates inresponse to variations in' the pressure in the stem Supply tothe turbineto drive the same; and'which is highly effective and foolproof inoperation and use.

While a particular embodiment of the present invention has beenillustrated and described herein, it is not intended to limit theinvention to such disclosure, and changes and modificaby to an extentthat may cause damage" or dis iitionsmay be made-therein and theretowithin the rupt the calibration or settings thereof andof" other devicesand controls that may bernountedi upon the same control'panel or boardas the swi ch II. Excess condensate formed in'the' coil" or condenser I9drains-or flows into the chamber I8.

lh the case of a: complete-failureprshut dovm ofthe steam supplyin-the'li e IE -tothe turbine I3. the pre sure in the line I5 betweenthe'va'ive I6 and turbine I! freuuently'is reduced to a m ne below'atmospheri'c pressure' thereby producin a; suction forcein-the-pipe-Mandchain her I 8 whicli t'ends to withdraw the condensatefrom the chamber lfa'nd thepipe IT. It is highly desirable thatprovision bemade toprevent wit drawal of" the water-condensatefrom thechamber IWand-tlie tube or pipe I! insuch cases and. in the presentinstance, this is ac compli'shed by the provision of'the aforesaid intake pipe or'tube-ZI and'one-way check valve lf'which operateto" admitatmospheric air into the c amber lB"'so that the suctionforce' in tlietube 2|! and chamber IB mereiy draws air' from the atmosphere inwardlythroughthe pipe 21 and chamber l8to the turbine I3without disturbing thewater condensateinsaid chamber' i B" and the pipe ortube I1.

In operation of the system and assuming: forpurposes of illustrationonly; that-thenormal operating steam pressure in the supply line I5 tothe'turbine I3'-is l5o'pounds' gauge and that the switch actuatingbellows or'diaphragm I2 "is 'con structed and arrangedto' hold theswitch II closed under such normal operating conditions and to open saidswitch, inthe event that the steam pressure in the-line ii'falls belowsay, 80 pounds gauge, it will be'apparentlfromtheforegoingdescriptionthat upontfailure of the steam pressure orupon shutdown'through operation the throttle I6, the steam pressure supply to theturbine in the line I5 almost'instantly will? fall below the 80 poundssetting of the Bellows or'diaphragm'fl; causing the latter to opewtheswitch: I l'thereby deenergizing the sole noid'B to actuate thepilotzvalve 5 and cause the checkvalve 4 to close'and prevent reverseflow from the line 3 through the centrifugal. pump I: In addition; it isto be notedthat instarting operation of'tlie' pump" system, as the steamthrottle I6 is* opened to warm the turbine I3 theinitial pressure willbe veri low but as the turbine speed is brought up to approach thenormal pumping speed a pressure of approximately 80 poundsgauge isreached thereby causmg the bellows or diaphragm I2 to close the switchII resulting in energization of the solenoidii and consequent operationof the pilot valve 5 to open the check valve 4,

From' the foregoing it will be seen that the present invention providesa novel control mechscopeof the claims.

Iclaim:

1. In a pumping system, a centrifugal pump having inlet and dischargepipes, a steam turbine operatively connected to said pump to drive thesame, a steamsupply'lineeto'saiditurbine, a check valve in thepumpidischargerpipe normally open during operation ofithe=pumpingsystem, valve operating mechanism:includingppressure responsivemeans constructedi and: arranged to effect closing of said check valveupon the pressure in said steam" supply-linei failingrbeidwapredetermined value; a pressure line connecting from said steam'supplyline tozsaid-pressure responsive means, a cooling'coillin saidrpressureline for condensing steam' therein; a closed chamber in said pressureline intermediate the steam'supply line and saidcoolingicoil to'recelveexcess condensate from-the latter, and-means connecting the interior ofsaid chamber to the atmosphere operable in the eventofgslib-atmosgiheric pressure in the'stea-m supply'line to preventwithdrawal of the condensate-fromsaidchamber andcooling coil.

2. In a pumping system; arcentrifugal pump having inlet and dischargepipes, a steam turbine operativelyconnected to said'pump to drive thesame, a steamsupply line to said turbine, a throttle valve in said-,linetocontrol thesupply of steam to said'turbine, aichecic valve in the pumpdischargepipe normally open during operation of the pumping system;valve operating mechanism including pressure responsive meansconstructed and-arranged to efiect closing of said check valve upon thepressurein saidsteam line betweenthe throttle and the turbine fallingbelow a predetermined value, and a pressure line connecting to saidpressure responsive means from said steamsupply line betweenthe-turbineand the throttle therein;

3. In a pumping system,- a centrifugal pump having inlet and dischargepipes, a steam turbine operativelyconnected to'said pump to drive thesame, a steam supply line to said turbine, a throttle valve in said lineto control the supply of steam to said turbine, a check valve in thepump discharge pipenormally open during operation of the pumping system,valve operating mechanism including pressure responsive meansconstructed and arranged to effect closing of said check valve upon the:pressure in said steam line between the throttle and the turbine fallingbelow a predetermined value, a pressure line connecting to said pressureresponsive meansfrom said steam supply line between the turbine and thethrottle therein, a cooling coil insaid pressure line for condensingsteam therein, a closed chamber in said pressure line intermediate thesteam supply line and said cooling coil to receive excess condensatefrom the latter, and means connectin the interior of said chamber to theatmosphere operable in the event of sub-atmospheric pressure in thesteam supply line to prevent withdrawal of the condensate from saidchamber and cooling coil.

4. In a pumping system, a centrifugal pump having inlet and dischargepipes, a steam turbine operatively connected to said pump to drive thesame, a steam supply line to said turbine, a check valve in the pumpdischarge pipe normally open during operation of the pumping system,means to operate said valve including a solenoid, an electrical circuitto energize said solenoid, normally closed switch means in saidelectrical circuit. pressure responsive means to actuate said switchmeans constructed and arranged to open said switch means and therebyclose said check valve upon the pressure in said steam line fallingbelow a predetermined value.

5. In a pumping system, a centrifugal pump having inlet and dischargepipes, a steam turbine operatively connected to said pump to drive thesame, a steam supply line to said turbine, a check valve in the pumpdischarge pipe normally open during operation of the pumping system,means to operate said valve including a solenoid, an electrical circuitto energize said solenoid, normall closed switch means in saidelectrical circuit, pressure responsive means to actuate said switchmeans, a pressure line connecting from said pressure responsive means tosaid steam supply line and subjecting said pressure responsive means tothe pressure in said steam line, said pressure responsive means beingconstructed and arranged to open said switch means and thereby closesaid check valve upon the pressure in said steam line falling below apredetermined pressure.

6. In a pumping system, a centrifugal pump having inlet and dischargepipes, a steam turbine operatively connected to said pump to drive thesame, a steam supply line to said turbine, a check valve in the pumpdischarge pipe normally open during operation of the pumping system,means to operate said valve including a solenoid, an electrical circuitto energize said solenoid, normally closed switch means in saidelectrical circuit, pressure responsive means to actuate said switchmeans, a pressure line connecting from said pressure responsive means tosaid steam supply line and subjecting said pressure responsive means tothe pressure in said steam line. said pressure responsive means beingconstructed and arranged to open said switch means and thereby closesaid check valve upon the pressure in said steam line falling below apredetermined pressure, a cooling coil in said pressure line forcondensing steam therein, a closed chamber in said pressure lineintermediate said cooling coil and the steam supply line to receiveexcess condensate from said cooling coil, and means connecting theinterior of said chamber to the atmosphere operable in the event orsub-atmospheric pressure in the steam supply line to prevent withdrawalof the condensate from said chamber and cooling coil.

7. In a pumping system, a centrifugal pump having inlet and dischargepipes, a steam turbine operatively connected to said pump to drive thesame, a steam supply line to said turbine, a throttle valve in said lineto control the supply of steam to said turbine, a check valve in thepump discharge pipe normally open during operation of the pumpingsystem, means to operate said valve including a solenoid, an electricalcircuit to energize said solenoid, normally closed switch means in saidelectrical circuit, pressure responsive means to actuate said switchmeans, a pressure line connecting from said pressure responsive means tosaid steam supply line between the turbine and throttle to subject saidpressure responsive means to the pressure in said steam line, saidpressure responsive means being constructed and arranged to open saidswitch means and thereby close said check valve upon the pressure insaid steam line falling below a predetermined pressure.

8. In a pumping system, a centrifugal pump having inlet and dischargepipes, a steam turbine operatively connected to said pump to drive thesame, a steam supply line to said turbine, a throttle valve in said lineto control the supply of steam to said turbine, a check valve in thepump discharge pipe normally open during operation of the pumpingsystem, means to operate said valve including a solenoid, an electricalcircuit to energize said solenoid, normally closed switch means in saidelectrical circuit, pressure responsive means to actuate said switchmeans, a pressure line connecting from said pressure responsive means tosaid steam supply line between the turbine and throttle to subject saidpressure responsive means to the pressure in said steam line, saidpressure responsive means being constructed and arranged to open saidswitch means and thereby close said check valve upon the pressure insaid steam line falling below a predetermined pressure, a cooling coilin said pressure line for condensing steam therein, a closed chamber insaid pressure line intermediate said cooling coil and the steam supplyline to receive excess condensate from said cooling coil, and meansconnecting the interior of said chamber to the atmosphere operable inthe event of sub-atmospheric pressure in the steam supply line toprevent withdrawal of the condensate from said chamber and cooling coil.

THEODORE C. M. MAUCH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,980,374 Bradshaw Nov. 13, 19342,067,479 Dahlstrand et a1. Jan. 12, 1937 2,220,327 Goit et al. Nov. 5,1940 2,384,420 Griswold Sept. 4, 1945

